1. Field of the Inventive Concepts
The inventive concepts disclosed herein generally relate to optical fibers, and more particularly, but not by way of limitation, to an optical fiber track system and to methods of using thereof.
2. Brief Description of Related Art
Optical fibers are flexible transparent fibers made of pure glass about as thick as a human hair. Recently, some plastic materials have also been used for manufacturing optical fibers, but plastics are generally less optically uniform than pure glass. This typically limits the use of currently available plastic optical fibers for short distances where the associated signal attenuation does not pose a significant problem. Optical fibers function as optical pipes, or waveguides, allowing a light beam to propagate along the optical fiber due to a phenomenon known as total internal reflection.
Total internal reflection is achieved when a light beam encounters a boundary between two materials with different refractive indexes at an angle lower than a certain angle referred to as the critical angle of incidence. The difference in refractive indexes and the critical angle of incidence prevent the light from leaking out of the fiber and cause it to reflect and propagate along the optical fiber instead. To achieve the needed difference in refractive indexes, optical fibers are typically cladded in one or more layers of materials having a desired refractive index different from the refractive index of the optical fiber. To ensure that the critical angle of incidence is not exceeded, optical fibers have a minimum bend radius, and bending the optical fiber beyond this minimum bend radius may cause signal degradation due to light leaking out of the optical fiber and/or physical or mechanical optical fiber damage.
Optical fibers may be bundled, braided, or otherwise grouped into optical fiber cables, which have found widespread use in the telecommunication and computing industries. One or more layers of opaque materials may be deposited onto individual optical fibers in an optical fiber cable to prevent light leaking out of one optical fiber from interfering with light travelling through adjacent optical fibers. Additionally, one or more layers of protective materials may be used to protect the optical fibers and the optical fiber cable from external light and damage due to environmental conditions such as moisture, abrasive particles, vibration, and the like.
Recent developments in opto-electrical devices have allowed the use of optical fibers in data networks by combining optical fibers and printed circuit boards. Typically, an opto-electrical module is used to convert electrical signals into optical signals, the optical signals are transferred via one or more optical fibers, and another opto-electrical module is used to convert the optical signals back into electrical signals at their destination. This technology has allowed significant increases of available network bandwidth and has resulted in transmitting data literally at the speed of light.
Printed circuit boards are currently used in a variety of electrical and opto-electrical devices, and generally have small sizes to allow for the reduction of size and weight of various devices. Optical fibers can be attached to a variety of printed circuit boards in order to interface with optical and electrical components, such as opto-electrical modules, optical fiber trays, optical splicers, and optical splitters, for example.
Due to the fixed length of optical fibers and the small size of printed circuit boards used in modern electronics, optical fibers frequently have to be routed, or looped, around a circuit board several times, while at the same time not being bent beyond their minimum bend radius.
Existing methods to secure optical fibers to printed circuit boards rely on optical fiber clips, optical fiber ties, optical fiber posts, or optical fiber trays. Such optical fiber clips, ties, and trays, however, result in inconsistent routing of the optical fibers, and do not protect the optical fibers from damage during device assembly and subsequent use.
During device assembly, the optical fibers are generally routed by hand through the use of clips, ties, or optical fiber trays. This may result in some optical fibers being bent beyond their minimum bend radius. Further, exposed optical fibers may be damaged or broken during subsequent device assembly steps due to their completely unprotected state. The proper installation and routing of optical fibers in the prior art largely depends on the skill of the installer, and as such may be inconsistent, expensive, and time-consuming.
Another problem posed by the constantly decreasing size of printed circuit boards is the lack of space to attach the clips, ties, or optical fiber trays routing the optical fibers. The designer of a printed circuit board typically takes into account the needed optical fiber attachments sites, and designs the various connections in the circuit board around the needed attachments sites. Typically, no electrical components may be mounted directly under the path of the optical fibers across the surface of the printed circuit board. Due to the limited space available on the printed circuit board, and the necessary coordination between several acceptable attachment sites as dictated by the minimum bend radius, the current procedure for attaching optical fibers to printed circuit boards is unsatisfactory and complicates the design process for printed circuit boards.
The clips, ties, and trays currently employed to route optical fibers across printed circuit boards control the routing of only a relatively small portion of the optical fibers, and large spans of optical fiber are left uncontrolled. As a result, optical fibers may shift, slip, or move during shipping, handling, and use of the device. Such optical fiber movement may lead to optical fiber damage and result in signal loss or attenuation. Further, large portions of optical fiber are left completely unprotected and susceptible to damage during device assembly, shipping, handling, and use.
Further, because some opto-electrical components are mounted at different elevations relative to a plane defined by the printed circuit board, the bend radius and the position of the optical fibers should be reliably and accurately controlled not only in a single plane, but in all three dimensions. Clips, ties, and optical trays currently available are generally inadequate to accurately control the routing of optical fibers in the plane of the printed circuit board, and even more inadequate to route fibers above or below the plane of the printed circuit board. Repeatability in routing of optical fiber is difficult to achieve using traditional fiber clips, ties, and trays, as well.
To this end, a need exists for an optical fiber track system and method for routing optical fibers using the same. It is to such an optical fiber track system and method for routing optical fibers that the inventive concepts disclosed herein are directed.